Printing device and printing system

ABSTRACT

When a printing interruption cause occurs during printing of an image on a printing medium, printing of a page being printed is completed, and further only a position mark is printed on a printing resumption page. Then, a printing unit is stopped, and a conveyance speed is decelerated to stop conveyance of the printing medium. Next, the printing medium is rewound so that printing is resumed from the printing resumption page. Thereafter, the conveyance speed is accelerated to a predetermined speed, and printing is resumed from the printing resumption page on which the position mark is printed.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a printing device configured to performprinting on a printing medium and a printing system configured toperform printing by connecting two printing devices via a reversingunit, and particularly relates to a printing device and a printingsystem having a pause function of interrupting printing during printingand then resuming the printing.

Description of Related Art

If a printing interruption cause (a matter that should interruptprinting) occurs while printing is performed on a printing medium byusing a printing device, the printing is interrupted, and the printingis resumed after the printing interruption cause is eliminated. However,there may be a blank portion between a page printed last before theprinting is interrupted and a page printed first after the printing isresumed. For example, Japanese Laid-Open Patent Publication No.2014-144608 discloses that, in order to overcome a problem that aprinting position on the front surface and a printing position on theback surface deviate from each other because the printing medium expandsand contracts when back surface printing is performed after printing ona front surface of a printing medium is performed and then the printingmedium is dried, printing is performed in consideration of expansion andcontraction of the printing medium in a width direction occurring duringdrying after the front surface printing. In addition, Japanese Laid-OpenPatent Publication No. 2016-144895 describes that in a case where athick portion is formed on a long belt-shaped printing medium at apredetermined cycle, printing is stopped before the thick portionreaches a printing region, and a relative position between a printinghead and a recording region is switched to a retraction position, andthe relative position between the printing head and the recording regionis switched to the printing position after the thick portion passesthrough the printing region, by which a periodic shift of the printingposition before and after the interruption of a printing process can besuppressed.

However, the printing method described in Japanese Laid-Open. PatentPublication. No. 2014-144608 is a method of correcting a positionalshift between an image printed on the front surface of the printingmedium and an image printed on the back surface of the printing medium.Therefore, in a case where after the printing resumption, the printingis performed on the same surface as the surface on which the printinghas been performed before the interruption, a blank portion appearsbetween the page printed before the interruption and the page printedafter the interruption. In addition, the printing method described inJapanese Laid-Open Patent Publication No. 2016-144895 can be applied tothe case where the printing medium has a thick portion periodically.However, even if the printing method is applied in a case wherecontinuous paper without a thick portion is used and printing is resumedafter printing interruption, it is not possible to prevent the blankportion from appearing between the page printed before interruption andthe page printed after interruption.

SUMMARY OF THE INVENT ION

In view of the above circumstances, an object of the present inventionis to provide a printing device and a printing system capable ofresuming printing so that a blank portion does not appear between a pageprinted before interruption and a page printed after interruption whenprinting is interrupted due to occurrence of a printing interruptioncause.

One aspect of the present invention is directed to a printing deviceconfigured to print an image over a plurality of pages on a firstsurface of a printing medium having a long belt shape, the printingdevice including:

-   -   a conveyance unit configured to convey the printing medium;    -   a printing unit configured to print an image by ejecting ink on        the first surface of the printing medium conveyed by the        conveyance unit; and    -   a control unit,    -   wherein the control unit includes:        -   a printing control unit configured to control operation of            the printing unit; and        -   a conveyance control unit configured to control operation of            the conveyance unit,    -   the printing control unit includes a printing interruption        control unit configured to control, when a printing interruption        cause occurs, the printing unit to interrupt printing operation        after completing printing of a printing-interruption-time last        page being printed on the first surface of the printing medium,        and further printing a position mark indicating a printing        resumption position on a printing resumption page that is a next        page of the printing-interruption-time last page, and    -   the conveyance control unit includes a conveyance speed control        unit configured to control, after interruption of printing        operation, the conveyance unit to start deceleration of a        conveyance speed of the printing medium and stop a conveyance of        the printing medium.

According, to the above-described configuration, when a printinginterruption cause (a matter that should interrupt printing) occurswhile an image is being printed on the printing medium, the printingunit completes printing of all the pages being printed, and further,stops printing operation after printing only the position markindicating the page to be printed first when the printing is resumed.Thereafter, the conveyance control unit controls the conveyance unit todecelerate and stop the printing medium. Therefore, the printing isresumed from the page with the position mark printed, and no blankportion appear between the page printed last before printinginterruption and the page printed first after printing resumption. As aresult, the occurrence of damaged paper is prevented.

Another aspect of the present invention is directed to a printing systemincluding: a first printing device configured to print a first image ona first surface of a printing medium including the first surface and asecond surface that is a back surface of the first surface; a secondprinting device configured to print a second image on the secondsurface; and a reversing unit provided between the first printing deviceand the second printing device and configured to reverse the firstsurface and the second surface,

-   -   wherein the first printing device includes:        -   a first conveyance unit configured to convey the printing            medium;        -   a first printing unit configured to print an image by            ejecting ink on the first surface of the printing medium            conveyed by the first conveyance unit; and        -   a first control unit,    -   wherein the first control unit includes:        -   a first printing control unit configured to control            operation of the first printing unit; and        -   a first conveyance control unit configured to control            operation of the first conveyance unit,    -   the first printing control unit includes a first printing        interruption control unit configured to control, when a printing        interruption cause occurs, the first printing unit to interrupt        printing operation after completing printing of a first        printing-interruption-time last page being printed on the first        surface of the printing medium, and further printing a first        position mark indicating a printing resumption position on a        first printing resumption page that is a next page of the first        printing-interruption-time last page,    -   the first conveyance control unit includes first conveyance        speed control unit configured to control, after interruption of        printing operation of the first printing unit, the first        conveyance unit to start deceleration of a conveyance speed of        the printing medium and stop conveyance of the printing medium,    -   the second printing device includes:        -   a second conveyance unit configured to convey the printing            medium;        -   a second printing unit configured to print an image by            ejecting link on the second surface of the printing medium            conveyed by the second conveyance unit; and        -   a second control unit,    -   the second control unit includes:        -   a second printing control unit configured to control            operation of the second printing unit; and        -   a second conveyance control unit configured to control            operation of the second conveyance unit,    -   the second printing control unit includes a second printing        interruption control unit configured to control, when a printing        interruption cause occurs, the second printing unit to interrupt        printing operation after completing printing of a second        printing-interruption-time last page being printed on the second        surface of the printing medium, and further printing a second        position mark indicating a printing resumption position on a        second printing resumption page that is a next page of the        second printing-interruption-time last page, and    -   the second conveyance control unit includes a second conveyance        speed control unit configured to control, after interruption of        printing operation of the second printing unit, the second        conveyance unit, to start deceleration of a conveyance speed of        the printing medium and stop conveyance of the printing medium.

According to the above-described configuration, when a printinginterruption cause (a matter that should interrupt printing) occurswhile an image is being printed on the printing medium, the firstprinting unit and the second printing unit complete printing of all thepages being printed, and further, stop printing operation after printingonly the posit on marks (the first position mark and the second positionmark) indicating the pages to be printed first when the printing isresumed. Thereafter, the first conveyance control unit and the secondconveyance control unit respectively control the first conveyance unitand the second conveyance unit to decelerate and stop the printingmedium. Thereby, the printing is resumed from the pages on which theposition marks (the first position mark and the second position mark)are printed, and no blank portion appear between the pages printed lastbefore printing interruption and the pages printed first after printingresumption. As a result, the occurrence of damaged paper is prevented.

These and other objects, features, modes, and advantageous effects ofthe present invention will become more apparent from the followingdetailed description of the present invention with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an overall configuration of aprinting device according to a first embodiment of the presentinvention.

FIG. 2 is a plan view showing one configuration example of a printingunit included in the printing device shown in FIG. 1 .

FIG. 3 is a block diagram showing a hardware configuration of thecontrol unit included in the printing device shown in FIG. 1 .

FIG. 4 is a functional block diagram showing a functional configurationof a control unit included in the printing device shown in FIG. 1 .

FIG. 5 is a flowchart showing a procedure of the printing device shownin FIG. 1 from occurrence of a printing interruption cause to printingresumption.

FIG. 6 is a diagram showing changes in the printing medium in theprinting device shown in FIG. 1 from the time of the occurrence of theprinting interruption cause to the time of printing resumption.

FIG. 7 is a schematic diagram showing an overall configuration of aprinting system according to a second embodiment of the presentinvention.

FIG. 8 is a block diagram showing apart of configurations of a firstcontrol unit and a second control unit included in the printing systemshown in FIG. 7 .

FIG. 9 is a flowchart showing a procedure of a first printing device anda second printing device from occurrence of a printing interruptioncause to printing resumption.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

1. First Embodiment

<1.1 Configuration of Printing Device>

FIG. 1 is a schematic diagram showing an overall configuration of aninkjet printing device 100 according to a first embodiment of thepresent invention. As shown in FIG. 1 , the inkjet printing device 100includes a printer body 110 and a control unit 120. The printer body 110includes a paper feeding unit 80 configured to hold a long belt-shapedprinting medium consisting of continuous paper rotatably around ahorizontal axis and supply the same, a printing mechanism 70 configuredto print an image by ejecting ink such as, for example, aqueous ink onthe printing medium supplied from the paper feeding unit 80 and toinspect the image after the printing medium is dried, and a winding unit90 configured to wind up the outputted continuous paper on whichprinting is completed. The control unit 120 controls operation of theprinter body 110 so that the image is printed on the printing medium onthe basis of job data given from outside.

The printing mechanism 70 includes a first driving roller 41 configuredto convey the printing medium supplied from the paper feeding unit 80 toan inside of the printing mechanism 70, a plurality of conveying rollers(also simply referred to as “rollers”) 43 for conveying the printingmedium inside the printing mechanism 70, a printing unit 10 configuredto perform printing by ejecting ink (e.g., aqueous ink) on thecontinuous paper, a drying unit 20 configured to dry the printing mediumby applying hot air to the printed printing medium, an inspection unit30 configured to inspect the printed image by collating the imageprinted on the printing medium with image data, and a second drivingroller 42 for outputting the printing medium from the printing mechanism70. The first driving roller 411 and the second driving roller 42 aredriven in conjunction with each other by a motor (not shown). Byswitching a rotation direction of the motor, regarding the printingmedium, conveyance to an upstream side in a conveyance direction andconveyance to a downstream side in the conveyance direction areswitched. The first driving roller 41, the second driving roller 42, andthe conveying rollers 43 configure a conveyance unit 40.

The printing mechanism 70 is provided with a reading, unit 50 configuredto read a position mark printed on a printing resumption page whenprinting is resumed after interruption. The reading unit 50 is disposedin the vicinity of the printing unit 10 and on the upstream side in theconveyance direction with respect to the printing unit 10 and on thedownstream side in the conveyance direction with respect to a positionof the position mark after the printing medium rewound. A reason why thereading unit 50 is disposed on the downstream side in the conveyancedirection with respect to the position of the position mark after theprinting medium is rewound is that the position of the position markprinted on the printing started page can be surely recognized when theprinting is resumed after the printing medium is rewound to the upstreamside. After the printing resumption, when the position mark printed onthe printing resumption page passes through the reading unit 50, thereading unit 50 notifies the control unit 120 that the printingresumption page has passed. As a result, the control unit 120 cancontrol the printing unit 10 so that the printing is resumed from theprinting resumption page (page to be printed first after printingresumption).

In addition, a rotary encoder 60 is disposed on the further upstreamside in the conveyance direction with respect to the printing unit 10.The rotary encoder 60 can measure a moving, distance of the printing,medium by counting a number of rotations of the first driving roller 41.Location of the rotary encoder 60 is not limited to the vicinity of anentrance of the printing mechanism 70, and the rotary encoder 60 may bedisposed in the vicinity of the second driving roller 42.

Although the configuration of the inkjet printing device 100 thatperforms color printing is shown in FIG. 1 as the configuration of theprinting device 100, an inkjet printing device configured to performmonochrome printing or a printing device configured to perform printingby another printing method can also be adopted.

FIG. 2 is a plan view showing one configuration example of the printingunit 10 included in the printing device 100 shown in FIG. 1 . As shownin FIG. 2 , the printing unit 10 is configured of inkjet head arrays15K, 10C, 15M, and 15Y for a K color (black), a C color (cyan color), anM color (magenta color), and a Y color (yellow color) arranged in linein the conveyance direction of the printing medium. Each of the inkjethead arrays is configured of a plurality of inkjet heads 16 arranged inzigzag. Each of the inkjet heads 16 includes a large number of nozzlesconfigured to eject ink. Each of the nozzles of the inkjet heads 16included in the inkjet head array 15K for the K color ejects ink of theK color, each of the nozzles of the inkjet heads 16 included in theinkjet head array 15C for the C color elects ink of the C color, each ofthe nozzles of the inkjet heads 16 included in the inkjet head array 15Mfor the M color ejects ink of the M color, and each of the nozzles ofthe inkjet heads 16 included in the inkjet head array 15Y for the Ycolor ejects ink of the Y color.

In the above description, a case where printing is performed by ejectingaqueous ink is exemplified. However, the present invention is notthereto, and the present invention can also be applied to a case wherean image is printed using UV ink (ultraviolet curing ink). Note that, inthe case of using the UV ink, it is necessary to cure the UV ink byultraviolet irradiation in order to fix the printed image on theprinting medium. Since the present invention can be applied to the caseof performing printing using either of the aqueous ink and the ink asdescribed above, a term “fixing unit” may be used instead of the “dryingunit”. In addition, while drying treatment is performed in the casewhere the aqueous ink is used, curing treatment is performed in the casewhere the UV ink is used, and thus a term “fixing treatment” may be usedas a term including the drying treatment and the curing treatment.

The inspection unit 30 captures an image after drying by the drying unit20 by an imaging element, and performs inspection by comparing thecaptured image with the image data sent from outside. However, thepresent invention is not limited thereto, and the configuration may besuch that an image and a barcode representing the image are printed bythe image the printing unit 10 and the inspection unit 30 performsinspection by reading the barcode and collating whether or not the imagerepresented by the barcode matches the printed image. Since the barcodecan be read even if the printed barcode not dried, it is also possiblethat the barcode is read immediately after printing and the collation isperformed using the barcode. In the case where the collation using thebarcode is performed before the printed image is dried, a positionalrelationship between the drying unit 20 and the inspection unit 30 isopposite to the positional relationship shown in FIG. 1 .

<1.2 Hardware Configuration of Control Unit>

FIG. 3 is a block diagram showing a hardware configuration of thecontrol unit 120 included in the printing device shown in FIG. 1 . Asshown in FIG. 3 , the control unit 120 includes a body 130, an auxiliarystorage device 121, an optical disk drive 122, a display unit 123, akeyboard 124, a mouse 125, and the like. The body 130 includes a CPU111, a memory 112, a first disk interface unit 113, a second diskinterface unit 114, a display control unit 115, an input interface unit116, an output interface unit 117, and a network interface unit 118. TheCPU 111, the memory 112, the first disk interface unit 113, the seconddisk interface unit 114, the display control unit 115, the inputinterface unit 116, the output interface unit 117, and the networkinterface unit 118 are connected to one another via a system bus. Theauxiliary storage device 121 is connected to the first disk interfaceunit 113. The optical disk drive 122 is connected to the second diskinterface unit 114. The display unit (display device) 123 is connectedto the display control unit 115. The keyboard 124 and the mouse 125 areconnected to the input interface unit 116. The printer body 110 isconnected to the output interface unit 117 via a communication cable. Acommunication line 5 is connected to the network interface unit 118. Theauxiliary storage device 121 is a magnetic disk device or the like. Anoptical disk 6 as a computer-readable recording medium such as a CD-ROMor a DVD-ROM is inserted into the optical disk drive 122. The displayunit 123 is a liquid crystal display or the like. The display unit 123is used to display information desired by an operator. The keyboard 124and the mouse 125 are used by a worker to input an instruction to thiscontrol unit 120.

The auxiliary storage device 121 stores a printing control program(program for controlling execution of printing processing by the printerbody 110) P. The CPU 111 implements various functions of the controlunit 120 by reading the printing control program P stored in theauxiliary storage device 121 into the memory 112 and executing theprogram. The memory 112 includes a RAM and a ROM. The memory 112functions as a work area for the CPU 111 to execute the printing controlprogram P stored in the auxiliary storage device 121. The printingcontrol program P is provided by being stored in the computer-readablerecording medium (non-transitory recording medium). That is, forexample, the user purchases the optical disk 6 as a recording medium ofthe printing control program P, inserts the optical disk 6 into theoptical disk drive 122, reads the printing control program P from theoptical disk 6, and installs the printing control program P in theauxiliary storage device 121. Alternatively, the printing controlprogram P transmitted via the communication line 5 may be received bythe network interface unit 118 and installed in the auxiliary storagedevice 121.

FIG. 4 is a block diagram showing a schematic functional configurationof the control unit 120 implemented by executing the printing controlprogram P. As shown in FIG. 4 , the control unit 120 includes a printingcontrol unit 160 configured to control operation of the printing unit10, a conveyance control unit 170 configured to control operation of theconveyance unit 40, and a communication unit 180 for communicating aprinting control status for the printing medium and a conveyance controlstatus of the printing medium with a communication unit of a secondprinting device 100 b described later, the communication being performedby using the communication line. While the control unit 120 furtherincludes an inspection control unit configured to control operation ofthe inspection unit 30 and a drying control unit configured to controloperation of the drying unit 20, these are omitted in FIG. 4 .

The printing control unit 160 includes a printing interruption controlunit 161. When a printing interruption cause occurs, the printinginterruption control unit 161 controls the printing unit 10 to interruptprinting operation after completing printing up to aprinting-interruption-time last page, which is the last page among pagesthat are being printed on the printing medium, and further printing aposition mark indicating a printing resumption position on a printingresumption page (page to be printed first after the printingresumption), which is the next page of the printing-interruption-timelast page. Other operations of the printing unit 10 are directlycontrolled by the printing control unit 160.

The conveyance control unit 170 includes a conveyance speed control unit171 and a rewinding control unit 172. When a printing interruption causeoccurs, after the printing up to the printing-interruption-time lastpage is performed and printing operation of the printing unit 10 isinterrupted, the conveyance speed control unit 171 controls theconveyance unit 40 to start decelerating a conveyance speed of theprinting medium, and further to stop the conveyance of the printingmedium after the printing-interruption-time last page is conveyed to thedrying unit 20. Thereby, the pages printed in a period from the time ofthe occurrence of the printing interruption cause to the time of theprinting interruption are dried.

The rewinding control unit 172 controls the conveyance unit 40 so thatthe printing medium is rewound until a distance from a position(printing resumption position) of the position mark printed on theprinting resumption page to the printing unit 10 becomes equal to orlonger than an acceleration distance required to obtain a conveyancespeed that allows the printing resumption page to be printed, before theconveyance of the printing medium is resumed for printing resumptionafter printing operation is interrupted. Specifically, a rewindingdistance of the printing medium is a total distance of a decelerationdistance from start of deceleration of the printing medium to stop ofthe conveyance of the printing medium, a length of the printing unit 10in the conveyance direction, and the acceleration distance required toaccelerate the printing medium to a printable speed after printingresumption. The rewinding distance of the printing medium is measured bythe rotary encoder 60 counting a number of rotations of the firstdriving roller 41. Other operations of the conveyance unit 40 aredirectly controlled by the conveyance control unit 170.

<1.3 Procedure from Printing Interruption to Resumption>

<1.3.1 Outline>

FIG. 5 is a flowchart showing a procedure of the printing device 100shown in FIG. 1 from occurrence of a printing interruption cause coprinting resumption. An outline of a procedure from the occurrence ofthe printing interruption cause to the resumption of printing will bedescribed with reference to the flowchart shown in FIG. 5 .

In the printing device 100, when an image is being printed on theprinting medium, whether or not a printing interruption cause hasoccurred is monitored (step S100). When the printing interruption causedoes not occur, whether or not a printing interruption cause occurs isfurther monitored while continuing printing. When a printinginterruption cause occurs, processing proceeds to step S110, and theprinting unit 10 completes printing of all the pages being printed.

After completion of printing of all the pages being printed at the timeof occurrence of the printing interruption cause, the printing unit 10prints the position mark on a page (printing resumption page) next tothe printing-interruption-time last page, the position mark indicatingthat the page is the first page at the time of printing resumption (stepS120). When the printing of the position mark is completed, the printingunit 10 stops printing operation (step S130). Next, the conveyance unit40 starts to decelerate the conveyance speed, conveys all the pages forwhich printing is completed after the occurrence of the printinginterruption cause to the drying unit 20, and stops the conveyance ofthe printing medium after the completion of the drying of all the pagesfor which printing is completed after the occurrence of the printinginterruption cause (step S140). The inspection by the inspection unit 30is then stopped (step S150) Thereafter, the conveyance unit 40 rewindsthe printing medium so that the printing resumption page is positionedat the printing resumption position on the upstream side (step S160).

In step S170, the printing device 100 stops the operation of theprinting mechanism 70 and waits until there is a printing resumptioninstruction. When the printing resumption instruction is given, theconveyance unit 40 conveys the printing medium to the downstream side inthe conveyance direction while accelerating the printing medium (stepS180) As a result, the conveyance speed is accelerated to the printablespeed before the printing resumption page reaches the printing unit 10,and the printing unit 10 is enabled to normally perform printing in stepS200 described later.

Thereafter, the position mark printed on the printing resumption page ofthe printing medium is read by the reading unit 50 disposed in thevicinity of the printing unit 10, and the printing unit 10 is notifiedthat the printing resumption page has passed through the reading unit 50(step S190). Then, the printing unit 10 receives the notification fromthe reading unit 50 and resumes printing from the printing resumptionpage (step S200).

<1.3.2 Details of Procedure>

FIG. 6 is a diagram showing changes in the printing medium in theprinting device 100 shown in FIG. 1 from the time of the occurrence ofthe printing interruption cause to the time of printing resumption. Withreference to FIG. 6 , a process from the time of the printinginterruption to the time of printing resumption will be divided intofour stages of a first stage to a fourth stage, and operation of theprinting mechanism 70 and a printing state of the printing medium ineach of the stages will be described.

Regarding FIG. 6 , a numeral attached to a top of each page represents apage number of each of the pages. In the printing unit 10, the inkjethead arrays 15K, 15C, 15W, and 15Y for the K color, the C color, thecolor, and the Y color are disposed in this order from the upstream sidein the conveyance direction toward the downstream side in the conveyancedirection, and thus the printing of each of the paces is also performedin this order. The position mark is printed with the K color ink ejectedfrom the inkjet head array 15K for the K color. First, the position markis printed, and then images of the K color, the C color, the M color,and the Y color are printed in this order. In FIG. 6 , a progress statusof printing can be Grasped by the printing mark for each of the colorsdrawn in each of the pages.

Regarding the first stage, the printing medium when the printinginterruption cause occurs during printing is shown. In this example, ineach of pages 1 to 16, the position mark, and images of the K color, theC color, the M color, and the Y color are printed. That is, printing ofthe pages 1 to 16 is completed. As for the pages 1 to 6, the drying bythe drying unit 20 is completed, and the inspection by the inspectionunit 30 is being performed. As for the page 7, although the drying iscompleted, it has not yet been conveyed to the inspection unit 30. Asfor the pages 8 to 14, the drying by the drying unit 20 is beingperformed. As for the pages 15 and 16, printing is completed, and itwill be conveyed to the drying unit 20.

Pages 17 to 20 are being printed in the printing unit 10. Specifically,as for the page 17, printing of the position mark and printing of theimages of the three colors of K, C, and M are finished. As for the page18, printing of the position mark and printing of the images of the twocolors of K and C are finished. As for the page 19, printing of theposition mark and printing of the image of K color are finished. As forthe page 20, only the position mark is printed.

Regarding the second stage, the printing medium on which printing to beexecuted before interrupting the printing when the printing interruptioncause occurs is completed is shown. Since the printing interruptioncause occurred during printing of the position mark on the page 20, theimages of the colors that have not yet been printed are sequentiallyprinted for each of the pages 17 to 20 being printed. As a result, theimages are printed on each of the pages up to the page 20, which is theprinting-interruption-time last page. Furthermore, after only theposition mark is printed on a page 21, which is the printing resumptionpage to be printed first at the time of printing resumption, theprinting unit 10 stops printing operation. Next, deceleration of theconveyance speed of the printing medium is started, and each of thepages 17 to 20, on which printing is completed, is conveyed into thedrying unit 20 while decelerating.

In the example shown in FIG. 6 , the position marks are printed not onlyon the page 21, which is the printing resumption page, but also on thepages 1 to 20 on which the images are printed. However, the presentinvention is not limited thereto, and the configuration may be such thatno position mark is printed on the pages on which the images are printedand the position mark is printed only on the printing resumption page.Furthermore, regarding the case where the position mark is printed alsoon each of the pages on which the images are printed, the position markto be printed on the page 21, which is the printing resumption page, maybe a mark having a shape different from that of the position markprinted on the other pages on which the images are printed.

Regarding the third stage, the printing medium in a rewound state toresume printing is shown. A position of the page 21, which is theprinting resumption page, is a position at which a distance to theinkjet head array 15K for the K color on the most upstream side of theprinting unit 10 is equal to or longer than a distance at which a speedthat allows the printing resumption page to be printed by accelerationof the conveyance speed can be obtained, and is a position on theupstream side of the reading unit 50.

Regarding the fourth stage, the printing medium when printing of thepage 21, which is the printing resumption page, is resumed is shown. Theconveyance speed of the printing medium is accelerated to a printablestate before the printing of the K color is started on the page 21 bythe inkjet head array 15K for the K color of the printing unit 10. Uponreading the position mark printed on the page 21, the reading unit 50notifies the printing unit 10 that the page 21 has passed. As a result,printing is resumed when the page 21 reaches the position of the inkjethead array 15K for the K color. Thereafter, similarly, by sequentiallycontrolling the respective inkjet head arrays 15C, 15K, and 15Y for theC color, the M color, and the Y color while conveying the printingmedium to the downstream side in the conveyance direction, the images ofthese colors are sequentially printed, and printing of the page 21 iscompleted. Similarly, images of the four colors are printed on a page 22and subsequent pages.

Note that the inspection performed before the printing interruption iscontinued until the conveyance unit 40 is stopped even after theprinting is interrupted. Therefore, after the printing resumption, theinspection does not need to be performed again for the page for whichthe inspection has already been completed, and the inspection may beperformed only for the page for which the inspection is not completedwhen the conveyance unit 40 is stopped. However, the inspection may beperformed again for the page for which the inspection has already beencompleted.

With respect to the example shown in FIG. 6 , by performing printing asdescribed above when the printing interruption cause occurs, a blankportion does not appear between the page on which the image is printedlast after the occurrence of the printing interruption cause and thepage 21 on which the image is printed first after the printingresumption. Therefore, the occurrence of damaged paper is prevented.

<1.4 Effect>

According to the present embodiment, when the printing interruptioncause (a matter that should interrupt printing) occurs during printing,of the image on the printing medium using the printing device 100, theprinting unit 10 completes printing of the page being printed when theprinting interruption cause occurred, and the printing medium is rewoundafter the printing medium is dried. After the printing interruptioncause is resolved, the printing medium is accelerated to a printablespeed, and printing is resumed from the printing resumption page onwhich the position mark is printed. Therefore, a blank portion does notappear between the printing-interruption-time last page, which is thepage printed last before the printing interruption, and the printingresumption page, which is the page to be printed first after printingresumption. This prevents the occurrence of damaged paper.

2. Second Embodiment

<2.1 Configuration of Printing System>

In the present embodiment, a printing system 200 in which two printingdevices (a first printing device 100 a and a second printing device 100b) are connected via a reversing unit 150 will be described. The twoprinting devices (the first printing device 100 a and the secondprinting device 100 b) configuring the printing system 200 both have thesame configuration as the printing device 100 in the first embodiment.In FIGS. 7 and 8 described later, components of the first printingdevice 100 a corresponding to the components of the printing device 100in the first embodiment are denoted by adding “a” to ends of thereference numerals, and components or the second printing device 100 bcorresponding to the components of the printing device 100 in the firstembodiment are denoted by adding “b” to ends of the reference numerals.This printing system 200, unlike the printing device 100 in the firstembodiment, the paper feeding unit 80 is provided only in the firstprinting device 100 a, and the winding unit 90 is provided only in thesecond printing device 100 b.

FIG. 7 is a schematic diagram showing an overall configuration of theprinting system 200 according to the second embodiment of the presentinvention. As shown in FIG. 7 , in the printing system 200 according tothe present embodiment, the first printing device 100 a configured toprint an image on a front surface (a first surface) of a printing mediumand the second printing device 100 b configured to print an image on aback surface (a second surface) of the printing medium are connected inseries via the reversing unit 150. Each of the first printing device 100a and the second printing device 100 b is an inkjet printing devicehaving the same configuration as the printing device 100 in the firstembodiment. In the printing system 200, first, the image is printed onthe first surface that is the front surface of the printing medium bythe first printing device 100 a, then the front surface and the backsurface of the printing medium are reversed by the reversing unit 150,and then the image is printed on the second surface that is the backsurface of the printing medium by the second printing device 100 b.

The first printing device 100 a includes a first control unit 120 a, anda first printing mechanism 70 a including a first printing unit 10 a, afirst drying unit 20 a, and a first inspection unit 30 a. The secondprinting device 100 b includes a second control unit 120 b, and a secondprinting mechanism 70 b including a second printing unit 10 b, a seconddrying unit 20 b, and a second inspection unit 30 b.

FIG. 8 is a block diagram showing a part of the configurations of thefirst control unit 120 a and the second control unit 120 b included inthe printing system 200 shown in FIG. 7 . The first control unit 120 aand the second control unit 120 b are configured to be communicable viathe communication unit 180 so as to be able to indicate operationstatuses and control statuses of the devices to each other. As a result,the first control unit 120 a and the second control unit 120 b cancooperatively control the conveyance operation and the like of theprinting medium between the first printing device 100 a and the secondprinting device 100 b. As shown in FIG. 8 , the first control unit 120 aincludes a first printing control unit 160 a configured to control thefirst printing unit 10 a and a first conveyance control unit 170 aconfigured to control the first conveyance unit 40 a The first printingcontrol unit 160 a includes a first printing interruption control unit161 a, and the first conveyance control unit 170 a includes a firstconveyance speed control unit 171 a and a first rewinding control unit172 a. Similarly, the second control unit 120 b includes a secondprinting control unit 160 b and a second conveyance control unit 170 b.The second printing control unit 160 b includes a second printinginterruption control unit 161 b, and the second conveyance control unit170 b includes a second conveyance speed control unit 171 b and a secondrewinding control unit 172 b. Hereinafter, a function of each of thecomponents will be described.

When a printing interruption cause occurs, the first printinginterruption control unit 161 a controls the first printing unit 10 a tointerrupt printing operation after completing printing up to a firstprinting-interruption-time last page, which is a last page among pagesthat are being printed on the first surface of the printing medium, andfurther printing a first position mark indicating a printing resumptionposition on a first printing resumption page, which is a next page ofthe first printing-interruption-time last page. Similarly, the secondprinting interruption control unit 161 b controls the second printingunit 10 b to interrupt printing operation after completing printing upto a second printing-interruption-time last page and further printing asecond position mark on a second printing resumption page. Thus, thefirst printing interruption control unit 161 a and the second printinginterruption control unit 161 b independently control the first printingunit 10 a and the second printing unit 10 b, respectively.

No buffer part is provided in the first conveyance unit 40 a and thesecond conveyance unit 40 b in the printing system 200. Therefore, whenconveying the printing medium in the printing system 200, the firstconveyance unit 40 a and the second conveyance unit 40 b need tosimultaneously convey the printing medium in a same direction at a samespeed. Therefore, the first conveyance control unit 170 a and the secondconveyance control unit 170 b need to cooperatively control the firstconveyance unit 40 a and the second conveyance unit 40 b, respectively,so that the printing medium is conveyed in the same direction at thesame conveyance speed by the first conveyance unit 40 a and the secondconveyance unit 40 b.

After the printing of the first position mark is completed, the firstconveyance speed control unit 171 a controls the first conveyance unit40 a to start to decelerate the conveyance speed of the printing mediumand to convey the first printing-interruption-time last page to thefirst drying unit 20 a. The second conveyance speed control unit 171 bsimilarly controls the second conveyance unit 40 b in this regard, thefirst conveyance speed control unit 171 a and the second conveyancespeed control unit 171 b cooperatively control the first conveyance unit40 a and the second conveyance unit 40 b, respectively, until the firstprinting-interruption-time last page is conveyed to the first dryingunit 20 a and the second printing-interruption-time last page isconveyed to the second drying unit 20 b.

The first rewinding control unit 172 a and the second rewinding controlunit 172 b cooperatively control the first conveyance unit 40 a and thesecond conveyance unit 40 b, respectively, so that the printing mediumis rewound after the drying of the first printing-interruption-time lastpage is completed in the first drying unit 20 a and the drying of thesecond printing-interruption-time last page is completed in the seconddrying unit 20 b. This allows the first conveyance unit 40 a and thesecond conveyance unit 40 b to cooperatively convey, the printingmedium. The first rewinding control unit 172 a controls the firstconveyance unit 40 a so that the printing medium is rewound until adistance from the printing resumption position of the first printingresumption page to the first printing unit 10 a becomes equal to orlonger than an acceleration distance required to obtain the conveyancespeed that allows the first printing resumption page to be printed whenthe printing is resumed, and the second rewinding control unit 172 bcontrols the second conveyance unit 40 b so that the printing medium isrewound until a distance from the printing resumption position of thesecond printing resumption page to the second printing unit 10 b becomesequal to or longer than an acceleration distance required to obtain theconveyance speed that allows the second printing resumption page to beprinted when printing is resumed.

Although not shown in FIG. 8 , the first control unit 120 a includes afirst inspection control unit configured to control the inspection bythe first inspection unit 30 a, and the second control unit 120 bincludes a second inspection control unit configured to control theinspection by the second inspection unit 30 b. The first inspectioncontrol unit and the second inspection control unit control the firstinspection unit 30 a and the second inspection unit 30 b, respectively,to inspect all the pages for which the inspection of the images printedon the printing medium is not completed, after the conveyance of theprinting medium is resumed.

A first reading unit 50 a configured to read the first position mark isdisposed in the vicinity of the first printing unit 10 a of the firstprinting device 100 a, and on an upstream side in a conveyance directionwith respect to the first printing unit 10 a and on a downstream side inthe conveyance direction with respect to a position of the firstposition mark after the printing medium is rewound. Similarly, a secondreading unit 50 b configured to read the second position mark isdisposed in the vicinity of the second printing unit 10 b of the secondprinting device 100 b, and on an upstream side in a conveyance directionwith respect to the second printing unit 10 b and on a downstream sidein the conveyance direction with respect to a position of the secondposition mark after the printing medium is rewound. After the conveyanceresumption of the printing medium, the first reading unit 50 a reads thefirst position mark printed on the printing medium, and notifies thefirst printing unit 10 a via the first printing control unit. 160 a thatthe first printing resumption page from which printing is to be resumedhas passed. Similarly, the second reading unit 50 b notifies the secondprinting unit 10 b via the second printing control unit 160 b that thesecond printing resumption page from which printing is to be resumed haspassed.

In addition, the first printing device 100 a and the second printingdevice 100 b include a first rotary encoder 60 a and a second rotaryencoder 60 b, respectively. The first rotary encoder 60 a finds aconveyance distance of the printing medium by counting a number ofrotations of the first driving roller 41 a, Similarly, the second rotaryencoder 60 b also finds a conveyance distance of the printing medium. Atotal distance of a deceleration distance, a rewinding distance, and anacceleration distance required in each of the first printing device 100a and the second printing device 100 b is found by each of the firstrotary encoder 60 a and the second rotary encoder 60 b.

<2.2 Outline of Procedure from Printing Interruption to Resumption>

FIG. 9 is a flowchart showing a procedure of the first printing device100 a and the second printing device 100 b from occurrence of a printinginterruption cause to printing resumption. An outline of the procedurefrom the occurrence of the printing interruption cause to the printingresumption will be described with reference to the flowchart shown inFIG. 9 .

In the printing system 200 including the first printing device 100 a andthe second printing device 100 b, when images are being printed on aprinting medium, whether or not a printing interruption cause hasoccurred is monitored (step S300). When the printing interruption causedoes not occur, whether or not a printing interruption cause occurs isfurther monitored while continuing printing. When a printinginterruption cause occurs, processing proceeds to step S310, and each ofthe first printing unit 10 a and the second printing unit 10 b completesprinting of all the pages being printed.

After completion of printing up to the first printing-interruption-timelast page, the first position mark is printed on the first printingresumption page in the first printing device 100 a, and after completionof printing up to the second printing-interruption-time last page, thesecond position mark is printed on the second printing resumption pagein the second printing device 100 b (S320). After completion of printingof the first position mark, the first printing unit 10 a stops printingoperation, and after completion of printing of the second position mark,the second printing unit 10 b stops printing operation (step S330).Next, the first conveyance unit 40 a and the second conveyance unit 40 bcooperatively start to decelerate the conveyance speed of the printingmedium, performs conveyance of the first printing-interruption-time lastpage to the first drying unit 20 a and conveyance of the secondprinting-interruption-time last page to the second drying unit 20 b,respectively, and stop the conveyance of the printing medium aftercompletion of drying (step S340) Then, the image inspection by the firstinspection unit 30 a and the image inspection by the second inspectionunit 30 b are stopped (step S350).

Thereafter, the first conveyance unit 40 a and the second conveyanceunit 40 b cooperatively rewind the printing medium so that the printingresumption pages (the first printing resumption page and the secondprinting resumption page) are positioned at the printing resumptionpositions on the upstream side (step S360). In step S370, the firstprinting device 100 a and the second printing device 100 b stop theoperation of the first printing mechanism 70 a and the second printingmechanism 70 b, respectively, and wait until there is a printingresumption instruction. When the printing resumption instruction isgiven, the first conveyance unit 40 a and the second conveyance unit 40b cooperatively convey the printing medium to the downstream side in theconveyance direction while accelerating the printing medium (step S380).As a result, the conveyance speed is accelerated to the printable speedbefore the first printing resumption page reaches the first printingunit 10 a and the second printing resumption page reaches the secondprinting unit 10 b, and the first printing unit 10 a and the secondprinting unit 10 b are enabled to normally perform printing in step S400described later.

Thereafter, the first position mark printed on a front surface side isread by the first reading unit 50 a, the first printing unit 10 a isnotified that the first printing resumption page has passed through thefirst reading unit. 50 a, the second position mark printed on a backsurface side is read by the second reading unit 50 b reads, and thesecond printing unit 10 b is notified that the second printingresumption page has passed through the second reading unit 50 b (stepS390). Then, the first printing unit 10 a and the second printing unit10 b resume printing from the first printing resumption page and thesecond printing resumption page, respectively (step S400).

<2.3 Effect>

According to the present embodiment, in the case where printing isperformed on the front surface and the back surface of the printingmedium by connecting the first printing device 100 a and the secondprinting device 100 b, for neither of the front surface nor the backsurface of the printing medium, a blank portion appears between the pageprinted last before printing interruption and the page printed firstafter printing resumption. This prevents the occurrence of damagedpaper.

<3. Others>

While the present invention has been described in detail above, theabove description is illustrative in all aspects and is not restrictive.It is understood that numerous other modifications and variations can bedevised without departing from the scope of the invention.

This application is an application claiming priority based on JapanesePatent Application No. 2021-050841 entitled “PRINTING DEVICE ANDPRINTING SYSTEM” filed on Mar. 24, 2021, and the contents of which areherein incorporated by reference.

What is claimed is:
 1. A printing device configured to print an image over a plurality of pages on a first surface of a printing medium having a long belt shape, the printing device comprising: a conveyance unit configured to convey the printing medium; a printing unit configured to print an image by ejecting ink on the first surface of the printing medium conveyed by the conveyance unit; a fixing unit configured to fix an image printed on the first surface of the printing medium by the printing unit to the printing medium; and a control unit, wherein the control unit includes: a printing control unit configured to control operation of the printing unit; and a conveyance control unit configured to control operation of the conveyance unit, wherein the printing control unit includes a printing interruption control unit configured to control, when a printing interruption cause occurs, the printing unit to interrupt printing operation after completing printing of a printing-interruption-time last page being printed on the first surface of the printing medium, and further printing a position mark indicating a printing resumption position on a printing resumption page that is a next page of the printing-interruption-time last page, wherein the conveyance control unit includes a conveyance speed control unit configured to control, after interruption of printing operation, the conveyance unit to start deceleration of a conveyance speed of the printing medium and stop a conveyance of the printing medium, wherein the conveyance speed control unit controls the conveyance unit so that the printing-interruption-time last page is conveyed to the fixing unit when causing the conveyance unit to stop the conveyance of the printing medium, wherein the conveyance control unit includes a rewinding control unit configured to control the conveyance unit so that the printing medium is rewound after fixing processing on the printing-interruption-time last page by the fixing unit is completed, and wherein the rewinding control unit controls the conveyance unit so that the printing medium is rewound until a distance from the printing resumption position of the printing resumption page to the printing unit becomes equal to or longer than an acceleration distance required to obtain a conveyance speed that allows the printing resumption page to be printed, before the conveyance of the printing medium is resumed for printing resumption after printing operation is interrupted.
 2. The printing device according to claim 1, wherein the rewinding control unit controls the conveyance unit so that the printing medium is rewound by a total distance of a deceleration distance from start of deceleration of the conveyance speed of the printing medium to stop of the conveyance of the printing medium, a length of the printing unit in a conveyance direction, and the acceleration distance.
 3. The printing device according to claim 1, wherein the conveyance unit includes a roller and a rotary encoder, and the distance at which the printing medium is being rewound when the conveyance of the printing medium is resumed for printing resumption is found by the rotary encoder counting a number of rotations of the roller.
 4. The printing device according to claim 1, further comprising a reading unit configured to read the position mark, the reading unit being disposed on an upstream side in a conveyance direction with respect to the printing unit and on a downstream side in the conveyance direction with respect to a position of the position mark after the printing medium is rewound, wherein when the conveyance of the printing medium is resumed after interruption of printing operation, the reading unit reads the position mark printed on the printing resumption page and notifies the printing control unit that the printing resumption page has passed.
 5. The printing device according to claim 1, wherein the position mark is printed only on the printing resumption page.
 6. The printing device according to claim 1, wherein the printing control unit controls operation of the printing unit so that a mark having a shape different from the position mark is printed on a page on which the image is printed.
 7. The printing device according to claim 1, further comprising an inspection unit configured to inspect an image printed by the printing unit, wherein the control unit further includes an inspection control unit configured to control operation of the inspection unit, and the inspection control unit controls the operation of the inspection unit to inspect images for all the pages for which the inspection is not completed when the conveyance of the printing medium is resumed after interruption of printing operation. 